Many current far-eye 3D displays are incapable of providing accurate out-of-focus blur on the retina and hence cause discomfort with prolonged use. This out-of-focus blur rendered on the retina is an important stimulus for the accommodation response of the eye and hence is one of the major depth cues. Properly designed integral displays can render this out-of-focus blur accurately. In this paper, we report a rigorous simulation study of far-eye integral displays to study their ability to render depth and the out-of-focus blur on the retina. The beam propagation simulation includes the effects of diffraction from light propagation through the free space, the apertures of lenslet and the eye pupil, to calculate spot sizes on the retina formed by multiple views entering the eye. Upon comparing them with the spot sizes from the real objects and taking into account depth of field and spatial resolution of the eye, we determine the minimum number of views needed in the pupil for accurate retinal blur. In other words, we determine the minimum pixel pitch needed for the screen of a given integral display configuration. We do this for integral displays with varying pixel sizes, lenslet parameters and viewing distances to confirm our results. One of the key results of the study is that roughly 10 views are needed in a 4 mm pupil to generate out-of-focus blur similar to the real world. The 10 views are along one dimension only and out-focus-blur is only analyzed for the fovea. We also note that about 20 views in a 4 mm pupil in one dimension in the pupil would be more than sufficient for accurate out-of-focus blur on the fovea. Although 2-3 views in the pupil may start triggering accommodation response as shown previously, much higher density of views is needed to mimic the real world blur.